U.S. patent number 8,858,045 [Application Number 13/692,903] was granted by the patent office on 2014-10-14 for reflector attachment to an led-based illumination module.
This patent grant is currently assigned to Xicato, Inc.. The grantee listed for this patent is Xicato, Inc.. Invention is credited to Gerard Harbers, Christopher R. Reed, Peter K. Tseng, John S. Yriberri.
United States Patent |
8,858,045 |
Harbers , et al. |
October 14, 2014 |
Reflector attachment to an LED-based illumination module
Abstract
An LED based illumination module includes a thermal interface
surface that is coupled to a thermal interface surface of a
reflector using engaging members that generate a compressive force
between the thermal interface surfaces. The engaging members may
be, e.g., protrusions that interface with recesses, spring pins,
formed sheet metal, magnets, mounting collar, etc. The reflector
may include a vented portion that is not optically coupled to the
LED based illumination module to allow air to pass through the
reflector.
Inventors: |
Harbers; Gerard (Sunnyvale,
CA), Reed; Christopher R. (San Jose, CA), Tseng; Peter
K. (San Jose, CA), Yriberri; John S. (San Jose, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Xicato, Inc. |
San Jose |
CA |
US |
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Assignee: |
Xicato, Inc. (San Jose,
CA)
|
Family
ID: |
48041957 |
Appl.
No.: |
13/692,903 |
Filed: |
December 3, 2012 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20130141918 A1 |
Jun 6, 2013 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61566996 |
Dec 5, 2011 |
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Current U.S.
Class: |
362/433;
362/249.02; 362/296.01; 362/434 |
Current CPC
Class: |
F21V
29/505 (20150115); F21V 7/06 (20130101); F21V
29/70 (20150115); F21V 29/713 (20150115); F21V
29/71 (20150115); F21V 17/105 (20130101); F21V
7/00 (20130101); F21V 17/164 (20130101); F21V
29/00 (20130101); F21K 9/62 (20160801); F21V
7/09 (20130101); F21Y 2105/10 (20160801); F21V
17/14 (20130101); F21V 23/06 (20130101); F21V
29/83 (20150115); F21Y 2115/10 (20160801) |
Current International
Class: |
F21V
23/06 (20060101); F21V 7/00 (20060101) |
Field of
Search: |
;362/433-436,247,249.02,296.01,311.02,545 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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20 2006 002 583 |
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Jun 2007 |
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DE |
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10 2007 03878 |
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Feb 2009 |
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DE |
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20 2010 000 007 |
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Mar 2010 |
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DE |
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1 826 480 |
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Aug 2007 |
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EP |
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WO 2004/071143 |
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Aug 2004 |
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WO |
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WO 2010/044011 |
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Apr 2010 |
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WO |
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WO 2011/025244 |
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Mar 2011 |
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WO |
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Other References
Invitation to Pay Additional Fees mailed on Apr. 5, 2013 for
International Application No. PCT/US2012/067797 filed on Dec. 4,
2012 , 7 pages. cited by applicant .
Machine Translation in English of Abstract of DE 10 2007 038787 A1
visited at www.espacenet.com on May 28, 2013, 2 pages. cited by
applicant .
International Search Report mailed on Jul. 15, 2013 for
International Application No. PCT/US2012/067797 filed on Dec. 4,
2012, 15 pages. cited by applicant.
|
Primary Examiner: Tso; Laura
Attorney, Agent or Firm: Silicon Valley Patent Group LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 USC 119 to U.S.
Provisional Application No. 61/566,996, filed Dec. 5, 2011 which is
incorporated by reference herein in its entirety.
Claims
What is claimed is:
1. An apparatus comprising: a reflector with a first tapered
feature and a first thermal interface surface; an LED based
illumination module with a second thermal interface surface; and a
mounting collar including a first member and a second member each
with a second tapered feature, wherein the second member is
moveable with respect to the first member, and wherein a movement
to an engaged position couples the first and second tapered
features and generates a compressive force between the reflector
and the LED based illumination module coupled to the first member
of the mounting collar.
2. The apparatus of claim 1, further comprising: a hinge element
coupled to first and second members of the mounting collar.
3. The apparatus of claim 1, further comprising: a buckle, wherein
the buckle fixedly couples the first member to the second member in
the engaged position.
4. The apparatus of claim 1, further comprising a thermally
conductive pad disposed between the first and second thermal
interface surfaces.
5. The apparatus of claim 1, wherein the first thermal interface
surface is a faceted surface with a first surface area, wherein a
first portion of the first surface area contacts the second thermal
interface surface when the first and second thermal interface
surfaces are brought into contact, and wherein a second portion of
the first surface area does not contact the second thermal
interface surface when the first and second thermal interface
surfaces are brought into contact generating a void between the
first and second thermal interface surfaces.
6. The apparatus of claim 5, wherein the second thermal interface
surface is a faceted surface with a second surface area, wherein a
first portion of the second surface area contacts the first thermal
interface surface when the first and second thermal interface
surfaces are brought into contact, and wherein a second portion of
the second surface area does not contact the first thermal
interface surface when the first and second thermal interface
surfaces are brought into contact generating the void between the
first and second thermal interface surfaces.
7. The apparatus of claim 1, wherein the first thermal interface
surface is a thin sheet flexibly bonded to the reflector.
8. The apparatus of claim 1, wherein the second thermal interface
surface is a thin sheet flexibly bonded to the LED based
illumination module.
9. An apparatus comprising: an LED based illumination module with a
first thermal interface surface; a reflector including a second
thermal interface surface; and a mounting collar including a first
member and a second member with a plurality of elastic mounting
members, wherein the mounting collar is operable to capture the
reflector by a movement of the second member relative to the first
member, and wherein the movement deforms the elastic mounting
members and generates a compressive force between the first and the
second thermal interface surfaces.
10. The apparatus of claim 9, further comprising: a hinge element
coupled to first and second members of the mounting collar.
11. The apparatus of claim 9, further comprising: a buckle, wherein
the buckle fixedly couples the first member to the second member in
an engaged position.
12. The apparatus of claim 9, further comprising a thermally
conductive pad disposed between the first and second thermal
interface surfaces.
13. The apparatus of claim 9, wherein the first thermal interface
surface is a faceted surface with a first surface area, wherein a
first portion of the first surface area contacts the second thermal
interface surface when the first and second thermal interface
surfaces are brought into contact, and wherein a second portion of
the first surface area does not contact the second thermal
interface surface when the first and second thermal interface
surfaces are brought into contact generating a void between the
first and second thermal interface surfaces.
14. The apparatus of claim 13, wherein the second thermal interface
surface is a faceted surface with a second surface area, wherein a
first portion of the second surface area contacts the first thermal
interface surface when the first and second thermal interface
surfaces are brought into contact, and wherein a second portion of
the second surface area does not contact the first thermal
interface surface when the first and second thermal interface
surfaces are brought into contact generating the void between the
first and second thermal interface surfaces.
15. The apparatus of claim 9, wherein the first thermal interface
surface is a thin sheet flexibly bonded to the LED based
illumination module.
16. The apparatus of claim 9, wherein the second thermal interface
surface is a thin sheet flexibly bonded to the reflector.
Description
TECHNICAL FIELD
The described embodiments relate to illumination modules that
include Light Emitting Diodes (LEDs).
BACKGROUND
The use of LEDs in general lighting is becoming more desirable.
Illumination devices that include LEDs typically require large
amounts of heat sinking and specific power requirements.
Consequently, many such illumination devices must be mounted to
light fixtures that include heat sinks and provide the necessary
power. The typically connection of an illumination devices to a
light fixture, unfortunately, is not user friendly. Consequently,
improvements are desired.
SUMMARY
An LED based illumination module includes a thermal interface
surface that is coupled to a thermal interface surface of a
reflector using engaging members that generate a compressive force
between the thermal interface surfaces. The engaging members may
be, e.g., protrusions that interface with recesses, spring pins,
formed sheet metal, magnets, mounting collar, etc. The reflector
may include a vented portion that is not optically coupled to the
LED based illumination module to allow air to pass through the
reflector.
Further details and embodiments and techniques are described in the
detailed description below. This summary does not define the
invention. The invention is defined by the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-1C illustrate a perspective view, a partial cut away view
and another partial cut away view of an exemplary luminaire.
FIG. 2A shows an exploded view illustrating components of an
exemplary LED based illumination module.
FIG. 2B illustrates a perspective, cross-sectional view of LED
based illumination module as depicted in FIG. 2A.
FIG. 3 illustrates a cut-away view of a luminaire in another
embodiment.
FIG. 4 illustrates a side view of a top facing heat sink and LED
based illumination module.
FIG. 5 illustrates a cutaway, top view of top facing heat sink
affixed to LED based illumination module.
FIG. 6 illustrates a perspective view of the bottom side of heat
sink.
FIG. 7 illustrates cross-section D of FIG. 6.
FIG. 8 illustrates the steps of aligning and replaceably coupling
heat sink with LED based illumination module.
FIG. 9A illustrates section A of FIG. 7 and depicts the alignment
of heat sink and LED based illumination module.
FIG. 9B illustrates section B of FIG. 7 and depicts the heat sink
rotated with respect to section A and the start of engagement of
the spring pin and the ramped shoulder groove.
FIG. 9C illustrates section C of FIG. 7 and depicts the heat sink
rotated to a fully engaged position where heat sink is coupled to
LED based illumination module.
FIGS. 10A and 11A illustrate a top and side view of a spring pin
aligned with shoulder groove along section A of FIG. 7.
FIGS. 10B and 11B illustrate a top and side view of spring pin
engaging shoulder groove along section B of FIG. 7.
FIGS. 10C and 11 C illustrate a top and side view of spring pin
engaged in shoulder groove along section C of FIG. 7.
FIG. 12 illustrates a perspective view of bottom facing heat sink,
LED based illumination module, and top facing heat sink including a
mounting collar portion.
FIG. 13A illustrates elastic mounting members in the aligned
position.
FIG. 13B illustrates elastic mounting members in the fully engaged
position after rotation of heat sink with respect to heat sink.
FIG. 14A illustrates a top, perspective view of a portion of heat
sink with ramp feature.
FIG. 14B illustrates a bottom, perspective view of heat sink with
ramp feature.
FIG. 15A illustrates a top, perspective view of a portion of heat
sink and FIG. 15B illustrates a bottom, perspective view of a
portion of heat sink.
FIG. 16A illustrates a cross sectional view of a portion of heat
sink, LED based illumination module, and bottom facing heat sink in
the aligned position with elastic elements in contact, but not
deformed.
FIG. 16B illustrates a cross sectional view of a portion of heat
sink, LED based illumination module, and bottom facing heat sink in
the fully engaged position after rotation of the heat sink.
FIG. 17 depicts an embodiment that includes a reflector, a top
facing heat sink, and an LED based illumination module coupled
together with a magnet.
FIG. 18 illustrates a top view of the heat sink and reflector
coupled to LED based illumination module as depicted in FIG.
17.
FIG. 19 is illustrative of another embodiment of a heat sink and
reflector coupled to LED based illumination module by a magnet.
FIG. 20A illustrates a side view of LED based illumination module,
a mounting collar assembly, and top facing heat sink.
FIG. 20B illustrates a top view of the mounting collar
assembly.
FIG. 21 illustrates a perspective, exploded view of LED based
illumination module, a mounting collar assembly, top facing heat
sink, and bottom facing heat sink.
FIGS. 22-23 illustrate a side view and a top view of an embodiment
of top facing heat sink with reflective surfaces and a vented
portion that includes openings to allow air flow through heat
sink.
FIG. 24A illustrates a portion of a thermal interface surface of
module.
FIG. 24B illustrates thin sheets bonded to thermal interface
surfaces.
FIG. 24C illustrates thermal interface surfaces in contact with
each other through the thin sheets.
FIG. 25A illustrates a cross-sectional view of a portion of a
faceted thermal interface surface.
FIG. 25B illustrates faceted thermal interface surfaces in
contact.
DETAILED DESCRIPTION
Reference will now be made in detail to background examples and
some embodiments of the invention, examples of which are
illustrated in the accompanying drawings.
FIGS. 1A-1C illustrate an exemplary luminaire 150. The luminaire
150 illustrated in FIG. 1A includes an LED based illumination
module 100 (shown in FIGS. 1B and 1C) and a top facing heat sink
130. Heat sink 130 may include other structural and decorative
elements (not shown). For example, heat sink 130 may be part of a
light fixture. In the embodiment depicted in FIGS. 1A-1C, luminaire
150 includes a reflector 140 mounted to top facing heat sink 130.
Reflector 140 includes an interior surface or surfaces that shape
light emitted from LED based illumination module 100. In some other
embodiments, reflector 140 may be part of top facing heat sink 130.
For example, heat sink 130 may include an interior surface or
surfaces that shape light emitted from LED based illumination
module 100. In some other embodiments, reflector 140 is mounted to
LED based illumination module 100 directly.
As illustrated in FIG. 1A, luminaire 150 is circular in shape. This
example is for illustrative purposes. Examples of illumination
modules of general polygonal and curved shapes may also be
contemplated. For example, an LED based illumination module 100
with a rectangular form factor is illustrated in FIGS. 2A-2B.
FIG. 1B illustrates a view of luminaire 150 with a portion of heat
sink 130 cut away to expose LED based illumination module 100. FIG.
1C illustrates a view of luminaire 150 with a portion of both heat
sink 130 and reflector 140 cut away to expose the output window 108
of LED based illumination module 100.
As illustrated in FIGS. 1A-1C, heat sink 130 is top facing. The
entire body of heat sink 130 extends forward (in the direction of
light output of luminaire 150) from LED based illumination module
100. As depicted in FIG. 1C a plane A is oriented parallel to
output window 108 and is located a distance H above the bottom
surface of LED based illumination module 100. In the depicted
embodiment, the heat sink extends forward in a direction normal to
plane A (indicated as surface normal N in FIG. 1C) from plane A. In
some embodiments, the entire body of heat sink 130 is located on
the top facing side of plane A and plane A may be located anywhere
from the bottom surface of LED based illumination module 100 to the
top of LED based illumination module 100. In this manner, luminaire
150 may be installed in applications where the total height of
luminaire 150 is constrained. Heat sink 130 is generally made from
a thermally conductive material, such as aluminum, copper, die cast
metal, etc. and is thermally coupled to illumination module 100.
Heat flows by conduction through illumination module 100 and heat
sink 130. Heat also flows via thermal convection over heat sink
130.
In one aspect, top facing heat sink 130 is operable to dissipate a
significant percentage of heat generated by LED based illumination
module 100 to the environment and is removably coupled to
illumination module 100, e.g., by means of threads, a clamp, a
twist-lock mechanism, or other appropriate arrangement. In some
embodiments, more than twenty five percent of heat generated by LED
based illumination module 100 is dissipated to the environment
through removable, top facing heat sink 130. In some other
embodiments, more than fifty percent of heat generated by LED based
illumination module 100 is dissipated to the environment through
removable, top facing heat sink 130. In some other embodiments,
more than seventy five percent of heat generated by LED based
illumination module 100 is dissipated to the environment through
removable, top facing heat sink 130. The different percentages of
heat dissipation are made possible based on the configuration of
the heat sink and whether another heat sink is located on the back
side of the LED based illumination module 100, and if so, the
configuration of that heat sink.
In some embodiments (e.g., the embodiment illustrated in FIGS.
1A-1C), reflector 140 is located within an envelope formed from top
facing heat sink 130. Reflector 140 may be used to direct light
emitted from illumination module 100. Reflector 140 may also be
made from thermally conductive material and may be thermally
coupled to any of illumination module 100 and top facing heat sink
130. In these embodiments, heat flows by conduction into thermally
conductive reflector 140 and is dissipated into the environment.
Heat also flows via thermal convection over the reflector 140.
Optical elements, such as a diffuser or reflector 140 may be
removably coupled to illumination module 100, e.g., by means of
threads, a clamp, a twist-lock mechanism, or other appropriate
arrangement.
Illumination module 100 includes at least one thermally conductive
surface that is thermally coupled to top facing heat sink 130,
e.g., directly or using thermal grease, thermal tape, thermal pads,
or thermal epoxy. For adequate cooling of the LEDs, a thermal
contact area of at least 50 square millimeters, but preferably 100
square millimeters should be used per one watt of electrical energy
flow into the LEDs on the board. For example, in the case when 20
LEDs are used, a 1000 to 2000 square millimeter heat sink contact
area should be used. Using a larger heat sink 130 permits the LEDs
102 to be driven at higher power, and also allows for different
heat sink designs, so that the cooling capacity is less dependent
on the orientation of the heat sink. In addition, fans or other
solutions for forced cooling may be used to remove the head from
the device.
FIG. 2A shows an exploded view illustrating components of an
exemplary LED based illumination module 100. It should be
understood that as defined herein an LED based illumination module
is not an LED, but is an LED light source or fixture or component
part of an LED light source or fixture. LED based illumination
module 100 includes one or more LED die or packaged LEDs and a
mounting board to which LED die or packaged LEDs are attached. FIG.
2B illustrates a perspective, cross-sectional view of LED based
illumination module 100 as depicted in FIG. 2A.
LED based illumination module 100 includes one or more solid state
light emitting elements, such as light emitting diodes (LEDs) 102,
mounted on mounting board 104. Mounting board 104 may be attached
to mounting base 101 and secured in position by mounting board
retaining ring 103. Together, mounting board 104 populated by LEDs
102 and mounting board retaining ring 103 comprise light source
sub-assembly 115. Light source sub-assembly 115 is operable to
convert electrical energy into light using LEDs 102. The light
emitted from light source sub-assembly 115 is directed to light
conversion sub-assembly 116 for color mixing and color conversion.
Light conversion sub-assembly 116 includes cavity body 105 and
output window 108, and optionally includes either or both bottom
reflector insert 106 and sidewall insert 107. Output window 108 is
fixed to the top of cavity body 105. Cavity body 105 includes
interior sidewalls which may be used to reflect light from the LEDs
102 until the light exits through output window 108 when
sub-assembly 116 is mounted over light source sub-assembly 115.
Bottom reflector insert 106 may optionally be placed over mounting
board 104. Bottom reflector insert 106 includes holes such that the
light emitting portion of each LED 102 is not blocked by bottom
reflector insert 106. Sidewall insert 107 may optionally be placed
inside cavity body 105 such that the interior surfaces of sidewall
insert 107 reflect the light from the LEDs 102 until the light
exits through the output window 108 when sub-assembly 116 is
mounted over light source sub-assembly 115.
In this embodiment, the sidewall insert 107, output window 108, and
bottom reflector insert 106 disposed on mounting board 104 define a
light mixing cavity 160 in the LED based illumination module 100 in
which a portion of light from the LEDs 102 is reflected until it
exits through output window 108. Reflecting the light within the
cavity 160 prior to exiting the output window 108 has the effect of
mixing the light and providing a more uniform distribution of the
light that is emitted from the LED based illumination module 100.
Portions of sidewall insert 107 may be coated with a wavelength
converting material. Furthermore, portions of output window 108 may
be coated with a different wavelength converting material. The
photo converting properties of these materials in combination with
the mixing of light within cavity 160 results in a color converted
light output by output window 108. By tuning the chemical
properties of the wavelength converting materials and the geometric
properties of the coatings on the interior surfaces of cavity 160,
specific color properties of light output by output window 108 may
be specified, e.g. color point, color temperature, and color
rendering index (CRI).
Cavity 160 may be filled with a non-solid material, such as air or
an inert gas, so that the LEDs 102 emit light into the non-solid
material. By way of example, the cavity may be hermetically sealed
and argon gas used to fill the cavity. Alternatively, nitrogen may
be used. In other embodiments, cavity 160 may be filled with a
solid encapsulant material. By way of example, silicone may be used
to fill the cavity.
The LEDs 102 can emit different or the same colors, either by
direct emission or by phosphor conversion, e.g., where phosphor
layers are applied to the LEDs as part of the LED package. Thus,
the illumination module 100 may use any combination of colored LEDs
102, such as red, green, blue, amber, or cyan, or the LEDs 102 may
all produce the same color light or may all produce white light.
For example, the LEDs 102 may all emit blue or UV light. When used
in combination with phosphors (or other wavelength conversion
means), which may be, e.g., in or on the output window 108, applied
to the sidewalls of cavity body 105, or applied to other components
placed inside the cavity (not shown), such that the output light of
the illumination module 100 has the color as desired.
The mounting board 104 provides electrical connections to the
attached LEDs 102 to a power supply (not shown). In one embodiment,
the LEDs 102 are packaged LEDs, such as the Luxeon Rebel
manufactured by Philips Lumileds Lighting. Other types of packaged
LEDs may also be used, such as those manufactured by OSRAM (Ostar
package), Luminus Devices (USA), Cree (USA), Nichia (Japan), or
Tridonic (Austria). As defined herein, a packaged LED is an
assembly of one or more LED die that contains electrical
connections, such as wire bond connections or stud bumps, and
possibly includes an optical element and thermal, mechanical, and
electrical interfaces. The LEDs 102 may include a lens over the LED
chips. Alternatively, LEDs without a lens may be used. LEDs without
lenses may include protective layers, which may include phosphors.
The phosphors can be applied as a dispersion in a binder, or
applied as a separate plate. Each LED 102 includes at least one LED
chip or die, which may be mounted on a submount. The LED chip
typically has a size about 1 mm by 1 mm by 0.5 mm, but these
dimensions may vary. In some embodiments, the LEDs 102 may include
multiple chips. The multiple chips can emit light of similar or
different colors, e.g., red, green, and blue. In addition,
different phosphor layers may be applied on different chips on the
same submount. The submount may be ceramic or other appropriate
material. The submount typically includes electrical contact pads
on a bottom surface that are coupled to contacts on the mounting
board 104. Alternatively, electrical bond wires may be used to
electrically connect the chips to a mounting board.
Along with electrical contact pads, the LEDs 102 may include
thermal contact areas on the bottom surface of the submount through
which heat generated by the LED chips can be extracted. The thermal
contact areas are coupled to heat spreading layers on the mounting
board 104. Heat spreading layers may be disposed on any of the top,
bottom, or intermediate layers of mounting board 104. Heat
spreading layers may be connected by vias that connect any of the
top, bottom, and intermediate heat spreading layers.
In some embodiments, the mounting board 104 conducts heat generated
by the LEDs 102 to the sides of the board 104 and the top of the
board 104. In one example, the top of mounting board 104 may be
thermally coupled to a top facing heat sink 130 (shown in FIGS.
1A-1C) via retaining ring 103. In other examples, mounting board
104 may be directly coupled to a heat sink, or a lighting fixture
and/or other mechanisms to dissipate the heat, such as a fan. For
example, mounting board retaining ring 103 and cavity body 105 may
conduct heat away from the top surface of mounting board 104.
Mounting board 104 may be an FR4 board, e.g., that is 0.5 mm thick,
with relatively thick copper layers, e.g., 30 .mu.m to 100 .mu.m,
on the top and bottom surfaces that serve as thermal contact areas.
In other examples, the board 104 may be a metal core printed
circuit board (PCB) or a ceramic submount with appropriate
electrical connections. Other types of boards may be used, such as
those made of alumina (aluminum oxide in ceramic form), or aluminum
nitride (also in ceramic form).
Mounting board 104 includes electrical pads to which the electrical
pads on the LEDs 102 are connected. The electrical pads are
electrically connected by a metal, e.g., copper, trace to a
contact, to which a wire, bridge or other external electrical
source is connected. In some embodiments, the electrical pads may
be vias through the board 104 and the electrical connection is made
on the opposite side, i.e., the bottom, of the board. Mounting
board 104, as illustrated, is rectangular in dimension. LEDs 102
mounted to mounting board 104 may be arranged in different
configurations on rectangular mounting board 104. In one example
LEDs 102 are aligned in rows extending in the length dimension and
in columns extending in the width dimension of mounting board 104.
In another example, LEDs 102 are arranged in a hexagonally closely
packed structure. In such an arrangement each LED is equidistant
from each of its immediate neighbors. Such an arrangement is
desirable to increase the uniformity of light emitted from the
light source sub-assembly 115.
FIG. 3 illustrates a cut-away view of luminaire 150 in another
embodiment. Top facing heat sink 130 and reflector 140 are
removably coupled to illumination module 100. For example, any of
top facing heat sink 130 and reflector 140 may be coupled to module
100 by a twist-lock mechanism. In this manner any of top facing
heat sink 130 and reflector 140 is aligned with module 100 and is
coupled to module 100 by rotating any of top facing heat sink 130
and reflector 140 about an optical axis (OA) of luminaire 150. In
the engaged position, an interface pressure is generated between
mating thermal interface surfaces 136 of any of top facing heat
sink 130 and reflector 140 and module 100. In this manner, heat
generated by LEDs 102 may be conducted via mounting board 104 into
any of top facing heat sink 130 and reflector 140.
In some embodiments, luminaire 150 includes an electrical interface
module (EIM) 120 within an envelope formed by top facing heat sink
130. The EIM 120 communicates electrical signals to mounting board
104. In the embodiment depicted in FIG. 3, electrical conductors
132 are coupled to heat sink 130 at electrical connector 133. By
way of example, electrical connector 133 may be a registered jack
(RJ) connector commonly used in network communications
applications. In other examples, electrical conductors 132 may be
coupled to heat sink 130 by screws or clamps. In other examples,
electrical conductors 132 may be coupled to heat sink 130 by a
removable slip-fit electrical connector. Connector 133 is coupled
to conductors 134. Conductors 134 are removably coupled to
electrical connector 121 mounted to EIM 120. Similarly, electrical
connector 121 may be a RJ connector or any suitable removable
electrical connector. Electrical signals 135 are communicated over
conductors 132 through electrical connector 133, over conductors
134, through electrical connector 121 to EIM 120. EIM 120 routes
electrical signals 135 from electrical connector 121 to appropriate
electrical contact pads on EIM 120. Electrical signals 135 may
include power signals and data signals. In the illustrated example,
spring pins 122 couple contact pads of EIM 120 to contact pads of
mounting board 104. In this manner, electrical signals are
communicated from EIM 120 to mounting board 104. Mounting board 104
includes conductors to appropriately couple LEDs 102 to the contact
pads of mounting board 104. In this manner, electrical signals are
communicated from mounting board 104 to appropriate LEDs 102 to
generate light.
FIG. 4 illustrates an embodiment suited for convenient removal and
installation of a top facing heat sink 130 operable to dissipate
heat generated by LED based illumination module 100. FIG. 4
illustrates a side view of a top facing heat sink 130 and LED based
illumination module 100 configured such that they may be coupled
together by aligning features of both the heat sink and the module
and rotating the top facing heat sink 130 with respect to the
module to complete the attachment. Top facing heat sink 130
includes elastic mounting members 161 positioned along an inwardly
facing surface 166 of heat sink 130. LED based illumination module
100 includes heat sink engaging members 162 positioned on a heat
sink (reflector) engaging surface 164 of LED based illumination
module 100, which is oriented perpendicular (or approximately
perpendicular) to the thermal interface surface 163. The heat sink
engaging members 162 are configured to engage elastic mounting
members 161 when heat sink 130 is brought into alignment with LED
based illumination module 100. As top facing heat sink 130 is
rotated with respect to LED based illumination module 100, thermal
interface surface 165 of heat sink 130 is brought into contact with
thermal interface surface 163 of LED based illumination module 100.
As elastic mounting members 161 are fully engaged in corresponding
heat sink engaging members 162, a compressive force is generated
between LED based illumination module 100 and heat sink 130 across
thermal interfaces 163 and 165. In this manner, heat generated by
LED based illumination module 100 flows from module 100 to heat
sink 130 and is dissipated by heat sink 130.
FIG. 5 illustrates a cutaway, top view of top facing heat sink 130
affixed to LED based illumination module 100. As depicted, elastic
mounting members 161 are located on surface 166 that faces inward
toward the center of LED based illumination module 100. In
addition, elastic mounting members 161 are engaged with heat sink
engaging members 162.
FIGS. 6-11 illustrate an embodiment suited for convenient removal
and installation of a top facing heat sink 130 to an LED based
illumination module 100. FIG. 6 illustrates a perspective view of
the bottom side of heat sink 130. In the depicted embodiment, heat
sink 130 includes a reflector surface to direct light emitted from
LED based illumination module 100. In the illustrated embodiment,
heat sink 130 includes two elastic mounting members 170. In the
depicted embodiment the elastic mounting members are spring pin
assemblies 170 positioned opposite one another near the perimeter
of heat sink 130. In another embodiment, additional spring pin
assemblies may be employed and positioned equidistant from one
another near the perimeter of module 100. In other embodiments, the
spring pin assemblies may not be positioned equidistant from one
another. This may be desirable to create a mechanism that allows
only one orientation between heat sink 130 and LED based
illumination module 100 when heat sink 130 is coupled to LED based
illumination module 100.
FIG. 6 illustrates a perspective view of top facing heat sink 130
with spring pins 170 installed. A section indicator D is
illustrated in FIG. 6. FIG. 7 illustrates cross-section D of FIG.
6. A spring pin assembly 170 includes a spring 171 and a pin 172.
In the illustrated embodiment, pin 172 includes a tapered head 173,
a shoulder 174, and a radial groove 175. In the illustrated
embodiment, spring 171 is a cup shaped c-clip. In other
embodiments, other spring mechanisms may be employed (e.g. coil
spring and e-clip). Pin 172 loosely fits through a hole 176
provided in heat sink 130. The diameter of shoulder 174 is greater
than the diameter of hole 176, thus pin 172 may only extend through
heat sink 130 to the position where shoulder 174 contacts the
bottom surface of heat sink 130. At this position, spring 171 is
inserted into radial groove 175 of pin 172. In this manner, spring
171 acts to retain pin 172 within hole 176. Spring 171 also
provides a restoring force acting in the direction of pin insertion
into hole 176 in response to a displacement of pin 172 in a
direction opposite the direction of pin insertion.
FIG. 8 illustrates the steps of aligning and replaceably coupling
heat sink 130 with LED based illumination module 100 in accordance
with the first embodiment. LED based illumination module 100
includes thermal interface surface 181 on the top face of LED based
illumination module 100. Heat sink 130 includes thermal interface
surface 180. LED based illumination module 100 includes heat sink
engaging members 182. In the illustrated example, the heat sink
engaging members are radially cut ramped shoulder grooves 182.
Shoulder grooves 182 are positioned on the face of LED illumination
module 100 to correspond with the position of spring pins 170.
In a first step, heat sink 130 is aligned with LED based
illumination module 100. As illustrated in FIG. 8, spring pins 170
are aligned with shoulder grooves 182 in the horizontal dimensions
x and y and in the rotational dimensions Rx, Ry, and Rz, then
module 100 is translated in the z dimension until the interface
surfaces 180 and 181 come into contact. After alignment, in a
second step, heat sink 130 is rotated with respect to LED based
illumination module 100 to couple heat sink 130 to LED based
illumination module 100.
Three section indicators, A, B, and C, are illustrated in FIG. 7.
Section A, illustrated in FIG. 9A, depicts the alignment of heat
sink 130 and LED based illumination module 100. In the aligned
position, spring pin 170 loosely sits within a blind hole portion
of ramped shoulder groove 182. In this position, shoulder 174 of
pin 172 remains in contact with the bottom surface of heat sink
130. Section B, illustrated in FIG. 9B, is a view of heat sink 130
rotated with respect to Section A and illustrates the start of
engagement of the spring pin 170 and the ramped shoulder groove
182. In this position, spring pin 170 contacts a tapered portion of
groove 182. As illustrated the tapered head of pin 170 makes
contact with the corresponding taper of groove 182. Section C,
illustrated in FIG. 9C, is a view of heat sink 130 rotated to a
fully engaged position where heat sink 130 is coupled to LED based
illumination module 100. In this position, spring pin 172 is
displaced by an amount, .DELTA., in the z direction with respect to
the bottom surface of heat sink 130. Shoulder 174 moves off of the
bottom surface of heat sink 130. As a result of this displacement,
spring 171 deforms and generates a restoring force in the direction
opposite the displacement of pin 172. This restoring force acts to
generate a compressive force between thermal interface surface 180
of heat sink 130 and thermal interface surface 181 of LED based
illumination module 100. Groove 182 ramps downward from the face of
LED based illumination module 100 as it is radially cut from the
initial aligned position to the engaged position. As a result, pin
172 is displaced in the z-direction as heat sink 130 is rotated
from the aligned position to the engaged position.
In another embodiment, LED based illumination module 100 includes
radially cut shoulder grooves 182 that are not ramped. FIGS. 10-11
are illustrative of this embodiment. FIG. 10A illustrates a top
view of spring pin 170 aligned with shoulder groove 182. Section A
of FIG. 7 is illustrated in FIG. 11A. FIG. 11A depicts the
alignment of heat sink 130 and LED based illumination module 100.
In the aligned position, spring pin 170 loosely sits within a blind
hole portion of shoulder groove 182. FIG. 10B illustrates a top
view of spring pin 170 engaging shoulder groove 182. Section B of
FIG. 7 is illustrated in FIG. 11B. In this view, heat sink 130 is
rotated with respect to Section A and illustrates the start of
engagement of the spring pin 170 and the shoulder groove 182. In
this position, the tapered surface of spring pin 170 contacts
shoulder groove 182. As illustrated the tapered head of pin 170
makes contact with groove 182. FIG. 10C illustrates a top view of
spring pin 170 engaged in shoulder groove 182. Section C of FIG. 7
is illustrated in FIG. 11C. In this view heat sink 130 is rotated
to a fully engaged position where heat sink 130 is coupled to LED
based illumination module 100. In this position, spring pin 172 is
displaced by an amount, .DELTA., in the z direction with respect to
the bottom surface of heat sink 130. Shoulder 174 moves off of the
bottom surface. As a result of this displacement, spring 171
deforms and generates a restoring force in the direction opposite
the displacement of pin 172. This restoring force acts to generate
a compressive force between thermal interface surface 180 of heat
sink 130 and thermal interface surface 181 of LED based
illumination module 100. Groove 182 remains at the same distance
from the face of LED based illumination module 100 as it is
radially cut from the initial aligned position to the engaged
position. Pin 172 is displaced in the z-direction as module 100 is
rotated from the aligned position to the engaged position by
sliding between the tapered surface of pin 172 along shoulder
groove 182.
FIGS. 12-16 illustrate yet another embodiment suited for convenient
removal and installation of a top facing heat sink 130 on an LED
based illumination module 100. FIG. 12 illustrates a perspective
view of bottom facing heat sink 131, LED based illumination module
100, and top facing heat sink 130 including a mounting collar
assembly 210. Bottom facing heat sink 131 includes a plurality of
pins 213. In the illustrated embodiment each pin 213 includes a
groove 216 configured to engage with ramp feature 212 of top facing
heat sink 130. In other embodiments pin 213 may include a head
configured to engage with ramp feature 212. Each pin 213 is fixedly
attached to bottom facing heat sink 131 (e.g. press fit, threaded,
fixed by adhesive). Alternatively each pin 213 may be cast or
machined as part of bottom facing heat sink 131. Pins 213 are
arranged outside the perimeter of illumination module 100 such that
module 100 may be placed between pins 213 such that the bottom
surface of module 100 comes into contact with the top surface of
bottom facing heat sink 131. Alternatively in some embodiments,
some or all of pins 213 may be arranged within or along the
perimeter of illumination module 100. In these embodiments, module
100 includes through holes such that pins 213 may pass through the
holes until the bottom surface of module 100 comes into contact
with the top surface of bottom facing heat sink 131. As
illustrated, pins 213 are arranged equidistant from one another and
are spaced such that illumination module 100 fits loosely between
the pins. In other embodiments, pins 213 may not be arranged
equidistant from one another. In these configurations, the lack of
symmetry of the elements may be used as an indexing feature to
align module 100 in a particular orientation with respect to bottom
facing heat sink 131.
As depicted in FIG. 12, top facing heat sink 130 includes a
reflector surface to direct light emitted from LED based
illumination module 100. Top facing heat sink 130 includes elastic
mounting members 211. In the illustrated embodiment, elastic
mounting members 211 are included as an integral part of at least a
portion of heat sink 130. For example, heat sink 130 may be a
formed sheet metal part including elastic mounting members 211 as
part of the single formed sheet metal part. In other examples,
elastic mounting members 211 may be cast or molded as part of a
single part heat sink 130. Top facing heat sink 130 may optionally
include tool feature 214. As illustrated tool feature 214 includes
a plurality of surfaces of heat sink 130. In the illustrated
embodiment a complementary tool (e.g. wrench) may be employed to
engage with the tool feature 214 of heat sink 130 to facilitate
assembly and increase the torque that may be applied to heat sink
130.
As depicted in FIG. 12, heat sink 130 includes ramp features 212.
In the illustrated example, ramp features 212 are formed into heat
sink 130 (e.g. by stamping, molding, or casting). In other
embodiments, ramp features 212 may be affixed to heat sink 130
(e.g. by soldering, welding, or adhesives).
In a first step, module 100 is captured between top facing heat
sink 130 and bottom facing heat sink 131. As illustrated, module
100 is placed within pins 213 and heat sink 130 is placed over
module 100. Heat sink 130 includes through holes 215 at the
beginning of each ramp feature 212. In the aligned configuration,
heat sink 130 is placed over module 100 such that pins 213 pass
through the through holes 215 of heat sink 130.
In a second step, heat sink 130 is rotated with respect to bottom
facing heat sink 131 to a fully engaged position. As discussed
above, heat sink 130 may be rotated directly by human hands, or
alternatively with the assistance of a tool acting on tool feature
214 to increase the torque applied to heat sink 130. As heat sink
130 is rotated, the grooves 216 of pins 213 engage with ramp
feature 212 and elastic mounting members 211 engage with surface
217 of module 100. Surface 217 is illustrated for exemplary
purposes, however, any surface of module 100 may used to engage
with elastic mounting members 211. Once engaged, the rotation of
heat sink 130 causes heat sink 130 to displace toward bottom facing
heat sink 131. Furthermore, as a result of the displacement,
elastic mounting members 211 deform and generate a compressive
force between module 100 and heat sinks 130 and 131.
FIG. 13A illustrates elastic mounting members 211 in the aligned
position. In the aligned position, elastic mounting members 211 are
in contact module 100, but are not deformed. FIG. 13B illustrates
elastic mounting members 211 in the fully engaged position after
rotation of heat sink 130 with respect to heat sink 131. In the
fully engaged position, elastic mounting members 211 are in contact
module 100 and are deformed. As discussed above, the deformation
generates a compressive force acting to capture LED based
illumination module 100 between heat sinks 130 and 131.
FIG. 14A illustrates a top, perspective view of a portion of heat
sink 130 with ramp feature 212. FIG. 14B illustrates a bottom,
perspective view of heat sink 130 with ramp feature 212.
FIG. 15A illustrates a top, perspective view of a portion of heat
sink 130 and FIG. 15B illustrates a bottom, perspective view of a
portion of heat sink 130. As discussed above, ramp feature 212 is
optional. In some embodiments, feature 212 is not a ramp feature,
but is simply a slot feature. The slot feature includes the cut-out
portion of feature 212, but remains in plane with the top surface
of reflector 140, rather than rising above the top surface as ramp
feature 212 is depicted. In these embodiments, in a first step,
heat sink 130 is placed over module 100 such that pins 213 pass
through holes 215 of reflector 140 as discussed above. However,
after elastic mounting members 211 come into contact with module
100, a force is applied to heat sink 130 in a direction normal to
the bottom surface of module 100 that causes elastic mounting
members 211 to deform and generate a force to press module 100 and
heat sink 130 together. In these embodiments, an aligned position
is reached when the grooves 216 of pins 213 align in the normal
direction with ramp feature 212. In a second step, reflector 140 is
rotated with respect to heat sink 130 to a locked position. In
these embodiments, grooves 216 slide within ramp feature 212 and
act to lock reflector 140 to heat sink 130.
FIG. 16A illustrates a cross sectional view of a portion of heat
sink 130, LED based illumination module 100, and heat sink 131. In
the aligned position, elastic mounting members 211 are in contact
module 100, but are not deformed. FIG. 16B illustrates the portion
of the heat sink 130, module 100, and heat sink 131 in the fully
engaged position after rotation of heat sink 130 with respect to
heat sink 131. In the fully engaged position, elastic mounting
members 211 are in contact with module 100 and are deformed. As
discussed above, the deformation generates a force acting to
capture module 100 between heat sink 130 and heat sink 131.
FIGS. 17-21 illustrate yet another embodiment suited for convenient
removal and installation of a top facing heat sink 130 from an LED
based illumination module 100.
FIG. 17 depicts an embodiment that includes a reflector 140, a top
facing heat sink 130, and an LED based illumination module 100
coupled together with a magnet 191. As depicted in FIG. 17, top
facing heat sink 130 includes a magnet 191 at the interfaces with
reflector 140 and LED based illumination module 100. In the
depicted embodiment, reflector 140 includes an amount of
magnetically conductive material 190 (e.g., ferrous metal) at the
interface between reflector 140 and top facing heat sink 130 to
facilitate a magnetic attraction force between reflector 140 and
top facing heat sink 130. Similarly, LED based illumination module
100 includes an amount of magnetically conductive material 192
(e.g., ferrous metal) at the interface between LED based
illumination module 100 and top facing heat sink 130 to facilitate
a magnetic attraction force between LED based illumination module
100 and top facing heat sink 130.
In some other embodiments, any of reflector 140 and LED based
illumination module 100 may be constructed from magnetically
conductive material. In these embodiments, magnetic materials 190
and 192 may not be required to attach reflector 140 and LED based
illumination module 100 to top facing heat sink 130 with magnet
191. However, magnetically conductive materials often do not
exhibit optimal thermal conduction properties and it may be
preferable to include a magnetically conductive material 190 that
is different than the material used to construct reflector 140 to
promote heat dissipation through reflector 140. Similarly, it may
be preferable to include a magnetically conductive material 192
that is different than the material used to construct LED based
illumination module 100 to promote heat dissipation through LED
based illumination module 100.
As depicted in FIG. 17, reflector 140 is stacked on heat sink 130
that is stacked on LED based illumination module 100. However,
other configurations may be contemplated. In some embodiments,
reflector 140 may be attached to LED based illumination module 100
directly with a magnet and heat sink 130 may also be directly
attached to LED based illumination module 100 with the same magnet
or a different magnet. In some other embodiments, heat sink 130
includes a reflector surface that directs light emitted from LED
based illumination module and reflector 140 may be omitted. In some
other embodiments, materials 190, 191, and 192 may all be magnetic
materials. Their polarity may be arranged such that when reflector
140, heat sink 130, and LED based illumination module 100 are
placed in close physical proximity to one another, a magnetic force
is generated between material 191 and 190 that couples reflector
140 and heat sink 130 together and a magnetic force is generated
between material 191 and 192 that couples heat sink 130 to LED
based illumination module 100 together. FIG. 19 offers an example
of a polarity structure to realize this arrangement.
FIG. 18 illustrates a top view of heat sink 130 and reflector 140
coupled to LED based illumination module 100 as depicted in FIG.
17. As depicted reflector 140 includes magnetically conductive
material 190 configured in a ring arrangement. Similarly, LED based
illumination module 100 includes magnetically conductive material
192 (not shown) configured in a ring arrangement. Magnets 191 are
arranged in three equal length segments spaced evenly apart along a
ring that matches up with the rings of magnetically conductive
material 190 and 192. In the depicted embodiment, heat sink 130 and
reflector 140 can be independently rotated about a central axis of
luminaire 150 as indicated by the arrow in FIG. 18. In some other
embodiments a mechanical feature may be included to constrain the
relative positions of heat sink 130 and reflector 140 with respect
to LED based illumination module 100. This may be desirable in
embodiments where any of heat sink 130 and reflector 140 are not
axisymmetric.
FIG. 19 is illustrative of another embodiment of heat sink 130 and
reflector 140 coupled to LED based illumination module 100 by a
magnet. In the depicted embodiment, luminaire 150 includes a
central axis 193. Central axis 193 is located in the geometric
center of output window 108 and is oriented normal to output window
108 of LED based illumination module 100. In the depicted
embodiment, reflector 140 includes an optical axis 194 that is not
aligned with central axis 193. This may occur, for example, in
embodiments where asymmetric reflectors are employed to generate
off-axis illumination patterns from luminaires. As described with
respect to FIG. 18, reflector 140 can be independently rotated
about central axis 193 and coupled to LED based illumination module
100 in any orientation. As such, the orientation of reflector 140
(and optical axis 194) with respect to luminaire 150 is infinitely
adjustable. An asymmetric reflector 140 may be constructed by
commonly available injection molding techniques. Some geometries
may require more complex mold designs (e.g., multiple actions) or
in some cases, a reflector may have to be molded in two parts that
are subsequently joined (e.g., by ultrasonic welding, adhesive,
etc.). In some examples, magnet material 190 may be incorporated
into reflector 140 by an insert molding technique. Although other
techniques may be contemplated.
FIG. 19 also illustrates an arrangement of magnet materials 190,
191, and 192 with their respective polarities aligned such that
reflector 140, heat sink 130, and LED based illumination module 100
are coupled together by attractive magnetic forces. Magnet
materials 190, 191, and 192 may be arranged in this manner for
desirable relative orientations of reflector 140, heat sink 130,
and LED based illumination module 100. In addition, magnet
materials 190, 191, and 192 may be arranged such that their
respective polarities result in repulsive magnetic forces that
repel any of reflector 140, heat sink 130, and LED based
illumination module 100 from one another. In this manner,
undesirable relative orientations of reflector 140, heat sink 130,
and LED based illumination module 100 may be avoided by preventing
attachment in undesirable orientations. This may be achieved, for
example by breaking magnet materials 190, 191, and 192 into
segments with opposite polarities such that only certain relative
orientations of heat sink 130, reflector 140, and LED based
illumination module 100 result in the generation of attractive
forces among these elements.
FIGS. 20A-20B illustrate yet another embodiment suited for
convenient removal and installation of a top facing heat sink 130
from an LED based illumination module 100.
FIG. 20A illustrates a side view of illumination module 100,
mounting collar assembly 200, and top facing heat sink 130. Heat
sink 130 includes a tapered surface 203 positioned at the perimeter
of heat sink 130. As depicted in FIG. 20A, surface 203 tapers
toward the center of heat sink 130 from the bottom of the heat sink
130 toward the top. Also, as depicted in FIG. 20A, surface 203 is a
continuous surface over the entire perimeter of heat sink 130. In
other embodiments, surface 203 may be positioned at several
discrete locations at the perimeter of heat sink 130, rather than
encompassing the entire perimeter.
FIG. 20B illustrates a top view of mounting collar assembly 200. As
depicted in FIG. 20B, mounting collar assembly 200 includes a fixed
retaining member 201 and a movable retaining member 202. Fixed
retaining member 201 and movable retaining member 202 are coupled
by hinge element 207 with an axis of rotation in a direction normal
to the output window 108 of module 100. In this arrangement,
movable retaining member 202 is operable to rotate about the axis
of rotation with respect to fixed retaining member 201. In some
embodiments fixed retaining member 201 is coupled to bottom facing
heat sink 131 by suitable fastening means. In some other
embodiments fixed retaining member 201 is coupled to LED based
illumination module 100 by suitable fastening means. For example,
fixed retaining member 201 may be coupled to LED based illumination
module 100 by screws 206. In other examples, fixed retaining member
201 may be coupled to LED based illumination module 100 by
adhesives or by a weld, or any combination of screws, weld, and
adhesives. Fixed retaining member 201 and movable retaining member
202 include tapered elements 204. The tapered surface of elements
204 matches the taper of tapered surface 203.
Top facing heat sink 130 is replaceably coupled to illumination
module 100 by placing heat sink 130 within fixed retaining member
201 of mounting collar assembly 200. Movable retaining member 202
is rotated with respect to fixed retaining member 201 to capture
heat sink 130 within mounting collar assembly 200. As movable
retaining member 202 is rotating closed, tapered elements 204 make
contact with heat sink 130 and capture heat sink 130 within
assembly 200 and LED based illumination module 100. In an aligned
position, the bottom surface of heat sink 130 is in contact with
LED based illumination module 100 and tapered elements 204 of
assembly 200 are in contact with heat sink 130. Buckle 205 of
moveable retaining member 202 is coupled to fixed retaining member
201 and moved to a closed position. Buckle 205 includes an elastic
element 208. As buckle 205 is moved to the closed position, elastic
element 208 deforms and a clamping force is generated that acts in
the direction of closure between the fixed and movable retaining
elements. The clamping force acting in the direction of closure
generates a force to press heat sink 130 against LED based
illumination module 100. The interaction between tapered elements
204 and tapered surface 203 of heat sink 130 causes a portion of
the clamping force to be redirected to the direction normal to the
bottom surface of heat sink 130. In this manner, deforming elastic
element 208 as movable retaining member 202 rotates to the fully
closed position generates a force acting to press heat sink 130
against LED based illumination module 100.
In the illustrated example, a buckle 205 is employed to couple
movable retaining member 202 to fixed retaining member 201. In some
embodiments, buckle 205 may be mounted to fixed retaining member
201 rather than member 202. In other embodiments, a screw, clip, or
other fixing means may be employed to drive and retain movable
retaining member 202 with respect to fixed retaining member 201 in
the closed position.
FIG. 21 illustrates yet another embodiment suited for convenient
removal and installation of a top facing heat sink 130. FIG. 21
illustrates a perspective, exploded view of illumination module
100, mounting collar assembly 220, top facing heat sink 130, and
bottom facing heat sink 131 in one embodiment. As depicted, top
facing heat sink 130 includes the reflector 140. However, in other
embodiments, a separate reflector (not shown) may be included.
Mounting collar assembly 220 includes a base member 221 and a
retaining member 222. Base member 221 and retaining member 222 are
coupled by hinge element 223. In this arrangement, retaining member
222 is operable to rotate about the axis of rotation of hinge 223
and move with respect to base member 221. In the depicted
embodiment, base member 221 is coupled to bottom facing heat sink
131 by suitable fastening means. However, in some other embodiments
base member 221 is coupled to LED based illumination module 100 by
suitable fastening means. In the illustrated example, base member
221 is coupled to bottom facing heat sink 131 by screws. In other
examples, base member 221 may be coupled to bottom facing heat sink
131 by adhesives or by a weld, or any combination of screws, weld,
or adhesives.
In the illustrated embodiment, illumination module 100 is placed
within base member 221. In this manner module 100 is aligned with
mounting collar assembly 210. Top facing heat sink 130 may be
passed through retaining member 222 as depicted. In other
embodiments, top facing heat sink may be passed from the top of
retaining member 222 through inlet features. In this manner, top
facing heat sink 130 is aligned with retaining member 222.
Together, top facing heat sink 130 and retaining member 222 are
rotated with respect to base member 221 to capture top facing heat
sink 130 within mounting collar assembly 220. Retaining member 222
includes elastic mounting members 224. As top facing heat sink 130
and retaining member 222 is rotating closed, elastic mounting
members 224 make contact with top facing heat sink 130 and generate
a compressive force between top facing heat sink 130 and
illumination module 100. Elastic mounting members 224 are
configured such that contact is made between top facing heat sink
130 and LED based illumination module 100 before retaining member
222 reaches a fully closed position. As a result, after initial
contact, elastic mounting members 224 deform until retaining member
222 reaches the fully closed position. In the illustrated example,
a threaded screw 225 is employed to couple retaining member 222 to
base member 221. In some embodiments, threaded screw 225 includes a
knurled surface operable by human hands to drive and retain
retaining member 222 with respect to base member 221 in the closed
position. In other embodiments, a buckle, clip, or other fixing
means may be employed to drive and retain retaining member 222 with
respect to base member 221 in the closed position. By deforming
elastic mounting members 224 as retaining member 222 rotates to the
fully closed position, members 224 generate a force acting to press
top facing heat sink 130 against LED based illumination module 100.
A thermal interface surface of top facing heat sink 130 contacts,
by way of example, thermal interface surface 181 of LED based
illumination module 100. A pliable, thermally conductive pad or
thermally conductive paste may be employed between the thermal
interface surfaces to enhance the thermal conductivity at their
interface. In this manner heat generated by LED based illumination
module 100 is dissipated to the environment through top facing heat
sink 130.
FIGS. 22-23 illustrate a side view and a top view of an embodiment
of top facing heat sink 130 suited for enhanced dissipation of heat
from LED based illumination module 100 without impacting the
optical properties of included reflector surfaces. As discussed
herein heat sink 130 is thermally coupled to LED based illumination
module 100 to promote the dissipation of heat generated by LED
based illumination module 100. As depicted, heat sink 130 includes
a reflective surface 230 with a first surface profile and another
reflective surface 231 with a second surface profile. Reflective
surfaces 230 and 231 are separated by a vented portion 232 of heat
sink 130 that includes openings to allow air flow through heat sink
130. The vented portion of heat sink 130 is not in the direct
optical path of light emitted from LED based illumination module
100. The surface profiles of reflective surface 230 and reflective
surface 231 are selected to promote uniform light output from
luminaire 150 in spite of the optical discontinuity in the
reflecting surfaces in heat sink 130 introduced by vented portion
232.
In one embodiment, the surface profile of reflective surface 230 is
a twenty degree compound parabolic concentrator (CPC) and the
surface profile of reflective surface 231 is a forty degree CPC
In some embodiments, heat sink 130 (including reflective surfaces
230 and 231 and vented portion 232) is manufactured as one part by
a molding process. However, in some other embodiments, the shapes
of reflective surfaces 230 and 231 may cause the molding of heat
sink 130 to be prohibitively difficult. In such embodiments, it is
desirable to construct heat sink 130 by combining multiple parts.
For example two molded parts may be joined (e.g., by chemical
bonding, friction bonding, welding, etc.).
Although the embodiments discussed above have been depicted as
operable to couple round shaped, top facing heat sinks to similarly
shaped LED based illumination modules, the embodiments are also
applicable to couple polygonal shaped, top facing heat sinks to
similarly shaped LED based illumination modules. For example, a
linear displacement, rather than a rotational displacement may be
employed to engage a top facing heat sink 130 to a LED based
illumination module 100.
Although, the thermal interface surfaces of heat sink 130 and
module 100 have been depicted as flat surfaces, non-ideal
manufacturing conditions may cause surface variations that
negatively impact heat transmission across their interface. FIGS.
24A-24C illustrate thermal interface surfaces configured for
improved thermal conductivity in the presence of manufacturing
defects present on the interfacing surfaces. FIG. 24A illustrates a
portion of a thermal interface surface of module 100 by way of
example. The illustrated portion may be a surface of a machined,
molded, or cast part, or may be sawn from a larger part. These
processes may result in surface imperfections that decrease the
heat transmission possible across the surface. In some examples,
the imperfections may be local incongruities in the surface as
highlighted in portion 256. In other examples, the imperfection may
be a surface roughness or dimensional errors that result in a
misalignment and limited contact surface area when the two surfaces
250 and 251 are brought together. FIG. 24B illustrates thin sheets
252 and 254 bonded to surfaces 250 and 251, respectively by bonding
material 253. Bonding material 253 fills surface incongruities such
as those illustrated in portion 256. Sheets 252 and 254 are made by
processes such as sheet rolling that assure a high degree of
surface flatness. By bonding sheet 252 to surface 250, a rough
surface is replaced with a smooth, flat surface. When surfaces 252
and 254 are brought into contact, as illustrated in FIG. 24C, the
amount of surface area at their interface is increased compared to
the scenario when surfaces 250 and 251 are brought into contact.
Surfaces 252 and 254 may also be repeatedly placed into contact and
separated without having to clean and reapply conductive grease or
pads, thus simplifying module replacement. Bonding material 253 is
thermally conductive and acts to transfer heat between sheet
surfaces 252 and 254 to surfaces 250 and 251, respectively. In
addition, bonding material 253 is compliant. As surfaces 250 and
251 are pressed together, compliant bonding material 253 deforms
such that flat surfaces 252 and 254 make full contact across the
entire interface despite surface roughness or dimensional errors
that would normally limit their contact surface area to an amount
less than their entire interface.
Although, the thermal interface surfaces of heat sink 130 and
module 100 have been depicted as flat surfaces, non-ideal
manufacturing conditions may allow surface contaminants to
negatively impact heat transmission across their interface. FIGS.
25A-25B illustrate faceted thermal interface surfaces configured
for improved thermal conductivity in the presence of contaminant
particles. FIG. 25A illustrates a portion of a faceted thermal
interface surface 260 of module 100 in a cross-sectional view by
way of example. The faceted thermal interface surface 260 may be a
machined, molded, or cast part. As illustrated faceted surface 260
has a saw-tooth shape with repeated raised features extending from
module 100. Each raised feature is flattened at the tip. Heat sink
130 includes a faceted thermal interface surface 261 with a
complementary saw-tooth shaped pattern with repeated raised
features extending from heat sink 130. FIG. 25B illustrates module
100 in contact with heat sink 130. As illustrated the repeated
pattern of raised portions of interface surfaces 260 and 261
interlock and generate a repeated sequence of thermal contact
interfaces 262. In addition, the repeated pattern of raised
portions of interface surfaces 260 and 261 interlock and generate a
repeated sequence of voids 263. The voids are generated because of
the flattened portion at the top of each raised feature of
interface surfaces 260 and 261. As surfaces 260 and 261 are brought
into contact, surface contaminants become trapped within voids 263
rather than becoming trapped between thermal contact interfaces
262. Contaminant particles trapped between thermal contact
interfaces 262 create separation at the thermal interface that
impedes heat transmission across the interface. Contaminant
particles filling voids 263 do not interfere with heat transmission
across the interface. In this manner, faceted surfaces 260 and 261
are shaped to promote improved heat transmission across their
interface by providing voids to trap contaminant particles that
would otherwise be entrapped between surfaces 260 and 261 and
reduce the thermal conductivity at their interface.
In many of the above-described embodiments, the thermal interface
surfaces of heat sink 130 and module 100 have been depicted as
being placed in direct contact. However, manufacturing defects in
the interfacing surfaces of module 100 and heat sink 130 may limit
the contact area at their thermal interface. However, in all
described embodiments, a pliable, thermally conductive pad or
thermally conductive paste may be employed between the two surfaces
to enhance thermal conductivity.
In some examples, the amount of deflection, .DELTA., discussed with
respect to the above-mentioned embodiments may be less than 1
millimeter. In other examples, the amount of deflection, .DELTA.,
discussed with respect to the above-mentioned embodiments may be
less than 0.5 millimeter. In other examples, the amount of
deflection, .DELTA., discussed with respect to the above-mentioned
embodiments may be less than 10 millimeters.
Although certain specific embodiments are described above for
instructional purposes, the teachings of this patent document have
general applicability and are not limited to the specific
embodiments described above. For example, module 100 is described
as including mounting base 101. However, in some embodiments, base
101 may be excluded. In another example, module 100 is described as
including an electrical interface module 120. However, in some
embodiments, module 120 may be excluded. In these embodiments,
mounting board 104 may be connected to conductors from heat sink
130. Accordingly, various modifications, adaptations, and
combinations of various features of the described embodiments can
be practiced without departing from the scope of the invention as
set forth in the claims.
* * * * *
References